The 3rd Generation Partnership Project (3GPP) has defined the IP Multimedia Subsystem (IMS) as the service engine or service delivery architecture for next-generation IP networks. The IMS includes a set of network nodes that provide various multimedia services and control calls in a mobile communication network environment. The IMS combines an Internet Protocol (IP) network with the mobile communication environment. Further, under standards developed by Open Mobile Alliance (OMA), there has been a convergence of messaging services called “Converged IP Messaging (CPM) Service” that is a Session Initiation Protocol (SIP)-based service capable of servicing users of conventional Short Message Service (SMS), Multimedia Messaging Service (MMS), and Instant Messaging (IM) services, etc., as well as users of CPM service.